Tukuk-OSCarbon Dioxide, Read Directly
The live number from NOAA — what it says and what it does not
Carbon dioxide is the gas of breath and fire: every animal exhales it, every flame turns air into it, and for two centuries humans have been doing so at an industrial scale. This page shows the actual measurement — no model, no estimate: flasks and analysers at NOAA’s Mauna Loa observatory in Hawaii and a global network, published freely.
Today at Mauna Loa
Today’s reading
427.0 ppm
The climb per year
+2.83 ppm/yr
Fifteen years of the global annual mean
Parts per million of carbon dioxide in the whole-world surface atmosphere, year by year — straight from NOAA’s global monitoring averages.
What the number means
280 → 420+ in 170 years
Before the industrial revolution the world’s air held about 280 ppm of CO₂. NOAA’s global annual means began in 1959 at roughly 336.9 ppm and now pass 420 — a level at least three million years older than any human ancestor.
Why the sawtooth is not noise
Northern forests and grasslands inhale CO₂ each summer and exhale it each winter, so the curve breathes seasonally by a handful of ppm while its baseline only climbs. The trend is the fingerprint of fossil carbon; the wobble is the living planet.
Your own contribution
A person exhales air that is about 4 percent CO₂ — roughly 40,000 ppm against the outdoor 420. Every breath you have ever taken added carbon the food chain just captured from the air; the industrial loop is the same loop, run too fast.
Where to argue with the number
CO₂ itself is not a poison at outdoor levels — it is 0.04 percent of air. Its weight is radiative: more of it holds more of the Earth’s outgoing heat. That physics, not toxicity, is why this dial matters to every country on the coast.
Related
How living things move this gas day by day: Breathing Life. The oxygen side of the same reaction: Oxygen Explained. City-by-city particulate and ozone readings: the world air ranking.